[Pkg-rust-maintainers] Bug#973414: rustc: produces non-baseline opcodes for compiler_builtins::int::udiv::__udivmoddi4 on i386

[James Addison]

Package: rustc
Followup-For: Bug #973414

> Today I plan to rebuild rustc on Debian i386 with RUSTC_FLAGS (different to
> RUSTFLAGS) configured for i686 during the build.  That's inspired by a comment
> here: https://github.com/rust-lang/rust/pull/31110#issuecomment-174327810
> 
> To implement that, I've temporarily added RUSTC_FLAGS to the list of
> per-architecture buildflags accepted by dpkg-buildflags on my system.  I don't
> know whether that's the best place to put that configuration, but it would
> allow it to be configured on a per-architecture basis in Debian.

That didn't work; the resulting libraries continue to contain NOPL opcodes,
indicating that their C components were not compiled to the correct baseline.

The environment variable was definitely exported to the build process, so
it seems likely that I chose an incorrect environment variable name and/or
value.